It’s common for herbicide applications applied under adverse weather to sometimes result in temporary chlorosis or yellowing of crop leaves. The same will happen occasionally with Beyond in Clearfield sunflower, generally under cool, humid conditions.

“I use the term ‘flash’ since it helps communicate that it’s a very transient, very temporary condition,” says Vince Ulstad, technical services representative for BASF, which makes Beyond.

The condition may occur when adverse growing conditions prevent the sunflower plants from breaking down the herbicide as quickly as it normally would. “Sometimes you’ll see it, sometimes you won’t and to varying degrees,” says Ulstad. The yellowing ‘flash’ typically would occur within three to seven days of the Beyond application, and the plants typically grow of it within seven to 10 days, with no yield consequences.

The Beyond label (online at www.cdms.net/ldat/ld5KR029.pdf) describes the yellowing this way:

“Occasionally, internode shortening and/or temporary yellowing of crop plants may occur following Beyond applications. These effects can be more pronounced if crops are growing under stressful environmental or hot and humid conditions. These effects occur infrequently and are temporary. Normal growth and appearance should resume within 1-2 weeks.” – Tracy Sayler